Video monitoring system with object masking

ABSTRACT

A video monitoring system is proposed, which is used to mask objects in a monitored scene that involve the privacy of an individual. Such objects include vehicle license plates or the person himself. An unmasking occurs when proof of legitimacy is entered. In a modification, a combination of a stationary camera and a moving camera also permits the masking of individual objects in the monitored scene.

CROSS-REFERENCE TO A RELATED APPLICATION

The invention described and claimed hereinbelow is also described inGerman Patent Application DE 10 158 990.5 filed on Nov. 30, 2001. ThisGerman Patent Application provides the basis for a claim of priority ofinvention under 35 U.S.C. 119(a)-(d).

BACKGROUND OF THE INVENTION

The invention is based on a video monitoring system.

The patent application DE 197 39 482 A1 has disclosed a video monitoringsystem that is activated as needed. When the video monitoring system isnot needed, either a shutter is placed in front of its camera or thescene being observed is set to a general out-of-focus setting.

SUMMARY OF THE INVENTION

The video monitoring system according to the invention with thecharacterizing features of the independent claim has the advantage overthe prior art that now, individual objects in a scene can be localizedand, depending on instructions, individual objects in the camera scenecan be masked. The masking is then switched off when a predeterminedevent occurs. In order to provide a camera monitoring that is acceptableto the public, it is advisable to use the video monitoring systemaccording to the invention, which prevents the identification of privateindividuals. In particular, it masks even moving objects dynamically andwith precise imaging. The exact masking of objects permits a betteroverview of the scene and therefore a detailed depiction of events andconduct. All actions can be observed in detail, without revealing theidentity of the person and thus invading privacy. In particular, thismethod makes it generally possible to monitor workplaces of employees,for example in the financial industry, within the limits of industriallaw. This masking can detect the entire scene upon entry of an object,or can detect a partial region of the scene, or can detect all movingobjects or a particular object, as well as partial regions of thisobject. For example, a person can be made up of a number of partialobjects. It is thus possible to define the face as a particular objector also to detect regions of the eye, the torso, and the legs asadditional objects. In vehicles, the license plate can be identified andmasked.

The masking can take place in the camera, directly as part of thedigitizing of the camera signal, before the image digitization andcompression, before image storage, or before transmission to the displaysystem.

Advantageous improvements of the video monitoring system disclosed inthe independent claim are possible by means of the steps taken andmodifications made in the dependent claims.

It is particularly advantageous that the masking means covers the atleast one object with a uniform color tone or shade of gray. As aresult, only the contours of the masked object can be seen on thedisplay of the video monitoring system.

It is also advantageous that the event that triggers the unmasking ofthe masked object is either a predetermined point in time and/or istriggered by an entry into an input device of the video monitoringsystem. This entry can be an authorization or proof of legitimacy, i.e.a code, which is entered either manually or vocally. The entry here isalso understood to include when the video monitoring system usesbiometric measurement methods to recognize a particular person aslegitimate. These biometric measurement methods include fingerprints,biometric measurement methods of the eyes, or image recognition of theperson per se. But this also includes voice recognition. This can bebroadened to the extent that this unmasking only occurs in the presenceof two observers that must each offer proof of legitimacy.

It is also advantageous that the video monitoring system according tothe invention also has a combination of stationary and moving cameras.Such panning and tilting cameras are used for object tracking and forenlarged observation of scene details. The masking is then executed viathe rotation angle of the moving camera in conjunction with thestationary general view image so that the masking always follows theobject. As a result, positions of moving objects can be masked outprecisely to the pixel. The moving camera is thus combined with thestationary camera and aligned so as to establish an unambiguous imagespecification for every attainable position of the panning and tiltingcamera based on the general view image of the stationary camera. As aresult, the camera image is masked in conjunction with the alreadylocalized object mask of the moving object so that no identification ispossible. To that end, the view of the second stationary camera isdisplayed on the moving camera.

The object identification is executed by the processor based on a colordistribution and/or a geometric form and/or a relationship of the firstgeometric form to a second geometric form and/or grayscale value ortexture information.

The localization of the object in the camera image is executed throughthe known method of object segmentation in image sequences of stationarycameras. By storing a camera image of a former point in time, the sceneis essentially portrayed without the moving object. This prior image isalso referred to as the reference image. Information about the positionof present objects can be obtained by subtracting the reference imagefrom the current image. A process of binarization and segmentation makesit possible to extract a mask that is precise to the pixel for eachobject. The novel feature of the method disclosed is the use of theobject mask to mask the camera image.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments of the invention are shown in the drawings andwill be explained in detail in the description that follows.

FIG. 1 is a block circuit diagram of the video monitoring systemaccording to the invention,

FIG. 2 shows the masking of a license plate, and

FIG. 3 shows the masking of a person's face.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The monitoring of areas, particularly in public spaces or areas thatadjoin public traffic zones, involves the problem of preserving andprotecting the privacy of the individuals involved.

Other uses for the video monitoring system involve workspaces thatrequire an observation and monitoring of actions and behaviors, but donot permit the identification of individuals in the first step. Onlywhen there is a concrete suspicion, for example of the commission ofillegal acts, can the identity protection be lifted with the aid of thecorrect proof of legitimacy. According to the invention, this isachieved here in that the video monitoring system according to theinvention masks individual objects in a monitored scene.

FIG. 1 shows a block circuit diagram of the video monitoring systemaccording to the invention. A camera 1 here is connected to a signalprocessing device 2 that is connected to a first data input of aprocessor 3. A second data input of the processor 3 is connected to asignal processing device 6, which is in turn connected to an inputdevice 7. A data input/output port connects the processor 3 to a memory12. The processor 3 is connected via a data output to an activating unit4, which activates a display 5 that shows the monitored scene.

Only one camera 1 is shown here by way of example. However, combinationsof different camera types or a number of cameras can be connected to oneanother, for example interconnected by means of a bus. In addition tonormal video cameras, it is possible to use other camera types such asinfrared cameras or other thermal imaging cameras. It is also possibleto use combinations of video cameras and thermal imaging cameras. Inaddition, the cameras are moving and/or stationary. Moving cameras makeit possible for objects to be tracked. The signal processing device 2processes the camera signals coming from the camera 1 and prepares themfor processing in the processor 3. The processor 3 executes an objectdetection with objects stored in the memory 12 in order to possibly maskout individual objects. The masking here is generated in the form of ahomogeneous gray cover. It is also possible to use a color or for themask to be kept colorless. The scene made up of the individual objectsis then transmitted to the activating unit 4, which then activates thedisplay 5. It is also possible here for more than one display to betriggered. The display 5 here is a normal monitor. However, flat screendisplays and other display techniques can also be used here. Thetransmission to the display 5 can also take place via the Internet orvia other data transmission lines. It is also possible for the display 5to be in a different location than the camera 1, for example in amonitoring station of a security service.

In order to execute an unmasking of the masked objects, a proof oflegitimacy is entered into the input device 7, whose signals theactivating unit 6 then pre-processes for the processor 3. The unmaskingis executed particularly if observation of the scene indicates thedanger of illegal activity. This can be automatically detected throughobject recognition or can also be detected by an observer. It is alsopossible here for alarms to be attached to other sensors.

The authorization can be executed by entering a code, through a personalidentification, through voice recognition, or, as explained above,through the use of biometric methods. It is also possible that theunmasking of objects is only executed if two separate individuals offerseparate proof of legitimacy. In particular, this hinders misuse. Theinput device 7 can be a keypad, a microphone, or a biometric measuringdevice such as a fingerprint sensor with the attendant electronics.

FIG. 2 shows a masking of a car 8 in which a license plate 9 is maskedby a gray blur. This makes it impossible to identify the vehicle, thusassuring the privacy of the vehicle owner. FIG. 3 shows another examplein which the facial area 11 of a person 10 is masked. It is thereforenot directly possible to identify the person. Unmasking for monitoringpurposes is only possible by entering proof of legitimacy.

1. A video monitoring system, wherein the video monitoring system has atleast one camera (1) for monitoring a scene, a processor (3) thatprocesses a camera signal, and a display (5) that shows the monitoredscene, wherein the processor (3) from a camera signal identifies atleast one object in the scene, localizes the at least one object, andextracts an object mask and that the video monitoring system has meansfor masking the at least one object with the object mask in the scene,wherein an unmasking occurs as a function of a predetermined event,wherein the video monitoring system has at least one stationary camerafor recording a general view of the scene and at least one moving camerafor recording a detail of the scene, wherein the mask is extracted fromthe stationary camera and the masking is adopted from the scene recordedby the stationary camera into the scene recorded by the moving camera.2. The video monitoring system according to claim 1, wherein the maskingmeans covers the at least one object with a uniform color tone or shadeof gray.
 3. The video monitoring system according to claim 1, whereinthe event is a predetermined point in time and/or an entry into an inputdevice (7) of the video monitoring system.
 4. The video monitoringsystem according to claim 3, wherein the entry is an authorizationand/or proof of legitimacy.
 5. The video monitoring system according toclaim 1, wherein the processor (3) executes the object identification inconjunction with a color distribution and/or a first geometric formand/or a relationship of the first geometric form to a second geometricform and/or a grayscale value or texture information.
 6. A videomonitoring system, wherein the video monitoring system has at least onecamera (1) for monitoring a scene, a processor (3) that processes acamera signal, and a display (5) that shows the monitored scene, whereinthe processor (3) from a camera signal identifies at least one object inthe scene, localizes the at least one object, and extracts an objectmask and that the video monitoring system has means for masking the atleast one object with the object mask in the scene, wherein an unmaskingoccurs as a function of one of: a predetermined event and adetermination that said at least one object has an association withillegal activity, wherein the video monitoring system has at least onestationary camera for recording a general view of the scene and at leastone moving camera for recording a detail of the scene, and wherein themask is extracted from the stationary camera and the masking is adoptedfrom the scene recorded by the stationary camera into the scene recordedby the moving camera.